Rotary cutter



my l, w24. 500,045

R. G. BARTLETT ROTARY CUTTER Filed Jan. 10, 1922 4 im@ c; 5W/55% Patented July l, l924.

isses,

ROTARY CUTTER,

application filed January 10, 1922.

To allwiomt may concern:

Be it known that I, Renner G. BARTLETT, a citizen of the United States, residing in Pleasantville, New Jersey, have invented. a Rotary Cutter, of which the following is a specification.

heY object of this invention is to provide a cutter particularly adapted tor cutting circular openings in sheet metal boxes and l0 the like, saidV cutter being adjustable for the purposel of cutting holes of different diameters and being provided with novel means whereby the tool may beV employed for accurately enlarging a circular opening already `formed.

In the attached drawings: Figure 1, is a view in, perspective of a tool made in accordance with my invention;

Fig. 2, is a fragmentary view, partially in section, of the cutter bearing end of the tool, and

Figs. 3 and 4, are views in perspective of collars of different sizes by means of which holes of specified diameters may be enlarged.

lith reference to the drawings, 1 represents the shank or body portion of the tool; in the present instance taking the Jform of the well known bit thereby to adapt the tool -for use with braces of standard construction. As best shown in Fig. 2, one end 2 of the shank 1 is of increased diameter with the extreme outer end of this enlarged portion 2 latted out at each side to form a diametrical tongue S, from the front and center of which tongue extends a threaded stem 4 coaxially arranged with respect to the body 1.

ln connection with the aforedescribed body portion, there is employed a. tool-carrying element 5, which element comprises in the present instance a substantially cylindrical end portion G, through which extends an opening 7 for the reception of a cutter 8 oi well known form. A set screw 9 extends from the top of the portion 6 into the opening 7 and provides means for securing the cutter 8 in the element 5. This latter element consists further of a lateral fiat extension 10 at one side of the head 6, which extension is slotted to receive therethrough the tongue 3 oit the body portion 1, as best shown in Figs. 1 and 2, the element 5 being held in place upon the tongue 3 of the body 1 by means of a nut 11, which is threaded Serial No. 528,274.

upon the stem 4. InV the present instance, a washer is shown disposed between the ele-- nient 5 and lthe inner lace of the nut 11.

As clearly shown, the nut 11 comprises, in addition to the usual polygonal portion, a cylindrical and p-reiferablyfslightly tapering extension 13, whichV extension is preferably internally threaded, as is the polygonal portionV of the nut for the passa-ge therethrough ofthe stem 4. The extensionY 13 is. adapted to receive. one or-other of a series of collars of dili'erent diameterssimilar to those illustrated in Figs. 3 and 4, Aand designated respectively bythe numerals 14 and 15. These collarsY are provided with set screws 16, which extend from the peripheryinto the inner opening 17, and provide means Jfor securing the collars to the said extension 13.,

The operation of the device is as follows:

The tool in the present instance is employed with a brace in the same manner as the ordinary bit. ln using this tool it is necessary lirst to bore a hole large enough to receive the extension 13 at the center of the larger hole which it is intended to form. This having been accomplished, the extension 13 is fitted in the hole and provides the central bearing for the tool, the body portion 1 being rotated by means of the brace in the u'sual manner and the point of the cutter 8 bearing against the side of the plate which is to be cut. The element 5 prior to the operation is so adjusted by loosening the nut 11 and sliding the said element upon the tongue 3 as to make the distance of the point of the cutter 8 from the axis of the body 1 to accord with the radius of the opening which it is desired to make.

It is often the case, particularly in metal boxes or such as are used by electricians or in the shells of meters and the like, that circular holes of dierent diameters are partially punched or pressed out of the boxes in such manner that a comparatively slight blow will knock out that portion of the box and thereby provide the opening. It is often desirable in such cases to enlarge these openings, and for this purpose I provide the col lars, such as 14 and 15. These collars are of such size as to correspond to the aforesaid partially pressed out circular portions, so that when these portions are forced out leaving the opening, the collars applied to the extension 13 may be passed into the said opening and provide the necessary bearing for accurate enlargement by means of the cutter 8.

In manufacturing this tool, it is preferred to providel therewith a series of collars of diameters corresponding to the openings ordinarily provided in the aforesaid electrical and meter boxes, the tool being in this manner rendered particularly valuable to electrical Workers.

It will be understood, however, that the tool is not confined to any particular use, since it may rind numerous applications, and to materials other than metal.

I claim:

l. In a tool, the combination With a body portion having at one end a iatted tongue, a threaded stem extending from the tongue coaxially with the body, a tool-carrying element having a slotted portion adapted to receive the said tongue, a. nut on said stem adapted to hold the tool-carrying element in place upon the body, a cylindrical co-aXial extension on the nut, and a cylindrical sleeve adapted to be detachably secured to said extension.

2. A tool comprising a body portion, a cutter element secured to said body portion at one side of the axis of the'latter in such manner that the cutter element may be adjusted laterally of said axis, a coaxial cylindrical extension at the end oi' the body portion, and .means 'for changing the diameter of said cylindrical extension.

3. A tool comprising a shank portion having at one end thereofl a tongue portion terminating in a threaded stem, an element having a slotted portion for the reception of said tongue portion, whereby said element .iay be moved transversely of said tongue,` one end of said slotted element being en-Y ROBERT G. BARTLETT. 

